1. Field of the Invention
The present invention relates to the field of bedding structures and particularly to bedding structures containing a liquid in at least one of the components of the structure. More particularly, the present invention relates to a waterbed structure made of a combination of components which provides a lightweight waterbed weighing no more than 200 pounds for a king-size waterbed, yet still retaining the support, comfort, and feel of a standard waterbed without the weight problems normally associated with these waterbeds.
2. Background Information
Since the late 1960's, water beds have been gaining popularity and wider acceptance for their comfort, body support and therapeutic value. This increased acceptance has occurred even though, water beds also have had numerous problems. Each year new water beds have been designed to try to correct these problems with new designs and new combinations of components.
One of these problems is the wave motion created in the water bed mattress when pressure is put on the mattress resulting in a wave rolling across the mattress, hitting the wall of the mattress and rolling back again. To counteract this problem, "hybrid" waterbeds have developed, which are composed of a water mattress with a foam topping placed over the mattress; however, these "hybrid" beds are as susceptible to wave motion as conventional waterbeds without the foam topping.
In continuing developments to counteract the wave motion problem, water beds have been designed with mattresses filled with water and resilient foam or cellulosic sponge called "baffles". The inclusion of these "baffles" have had some effect in reducing this wave phenomenon problem but they did not completely eliminate it and created problems of their own. Further, these waterbed systems generally cost more to manufacture as a result of their increased complexity. U.S. Pat. Nos. 4,411,033, and 4,532,662 disclose mattresses composed of unitary water filled bladders containing these "baffles". U.S. Pat. No. 4,912,789 discloses a combination of elongated water and "baffles" filled bladders covered by flat rectangular water filled bladders containing "baffles" contained in a frame made of resilient cushion material. U.S. Pat. No. 5,077,848 discloses a tube-type waterbed mattress with a plurality of elongated tubes containing "baffles" which are thicker in the center portion of the tube to add support to the area of the mattress which supports the lumbar area of the back. The elongated tubes are held in a soft-sided foam frame.
Another problem of conventional waterbeds is that the user experienced hammock-like support; that is, the trunk of the body of the user sank lower into the mattress while the arms, legs and head were pushed up. The inclusion of "baffles" within the mattress, like those to reduce wave action, provided only minimal improvement of this problem.
Still another problem is the "bottoming out" effect which results because the conventional waterbed mattress is placed upon a rigid plane to provide uniform support for the entire lower surface of the waterbed mattress. The conventional solution to this problem has been to fill the waterbed mattress to a depth of nine to twelve inches to avoid the user reaching the bottom of the mattress when a sudden force is applied to a localized area. However, even when this depth of water is used, it is still possible to hit bottom. Deep filling the mattress to this depth creates other problems, such as the great lateral outward force created by all of the water held in the mattress, requiring the addition of a strong, heavy frame to support the force of the great amount of water. This heavy frame is uncomfortable to sit on and, even if padded, there is a tendency to fall inward onto the waterbed mattress.
Further, the deep fill solution makes the water bed extremely heavy. A waterbed mattress filled to a nine inch or greater fill alone weighs approximately 2000 pounds and with the massive frame required to support this mattress, it weighs considerably more. Many residential structures were not designed to support this large concentration of weight.
Additionally, it is difficult to have such a large volume of water reach thermal equilibrium in ambient room temperatures. Therefore, unless the water is heated, substantial condensation occurs on the waterbed surface. Utilizing electric heaters to have the water reach thermal equilibrium is expensive and can represent a safety hazard.
Therefore, it can be seen that the proposed solutions to the problems of conventional waterbed mattresses do not completely overcome these problems and in some instances, such as using a deep fill water mattress, the solution results in additional problems, which include the extremely heavy weight, uncomfortable edge sitting, tendency of tumbling onto the water bed mattress from the edge, need to heat and control the temperature of the water in the mattress, and the resulting safety hazard of using a heater.
Taken individually or collectively, none of the prior art waterbed systems suggest the lightweight waterbed structure of the present invention, which combines the features of a lightweight foam base with generally flat profile multiple water bladders covered by a convoluted foam pad. The combination of components eliminates all of the problems associated with conventional water beds, provides many advantages over conventional water beds, and provides the user with an extremely lightweight waterbed which has the feeling and sensation of a heavier waterbed.